Phineas and Ferb Wandering over Gravity Falls
by CrossoverGuy21
Summary: Sequel to Wander over Gravity Falls. Bill the dream demon has risen again and vows to take over the universe, starting with Earth. Wander and Sylvia hear about this, and go to Earth to warn Dipper and Mabel. While they do, they meet Phineas and Ferb, so the brothers decide to help them. Features songs "Summer Belongs to You" and "Wander over Yonder."
1. 1: The Reunion

**Ever since November of 2013, you have waited...for so long...for a sequel...to Wander over Gravity Falls. Well, now...it's here. And this time, I am crossing over not just Disney's Wander over Yonder and Disney's Gravity Falls, but I'm also crossing over...wait for it...DISNEY'S PHINEAS AND FERB! So I bring you: Phineas and Ferb Wandering over Gravity Falls! And it starts...NOW!**

_**P.S. I do not own any of these shows or the Walt Disney coorperation, so don't remove this fanfic please.**_

**Phineas and Ferb Wandering over Gravity Falls Chapter 1: The Reunion**

It has been three weeks since Wander and Sylvia left Earth. It all started when they have crash-landed on Earth, in a little town named Gravity Falls, and met two twins named Dipper and Mabel.

They have had one amazing adventure and made two new friends. But now, not only is planet Earth in danger, but the whole universe lies in the balance of not only Wander, Sylvia, Dipper, and Mabel, but two other kids named Phineas Flynn and Ferb Fletcher as well.

It all started on July 11th. A young world traveler was exploring the forest of Gravity Falls. He has been walking in the forest for hours, hoping to discover something incredible.

"Man, if I don't find something soon," the traveler said. "this trip to Gravity Falls will be for nothing." Then he tripped over some sort of rock. But as he was getting up, something glew. It looked like some sort of temple. The traveler noticed there was something written on the walls.

"Well, what's this?" he wondered. He went up to the strange markings, but they weren't in English. Luckily, he knew heirogliphics. He translated aloud:

"Summonius Destructious Destroius!"

For a little bit nothing happened. The traveler felt that his time has been wasted, so he started to walk away. Then the ground started to rumble. Then a glow appeared behind him. The traveler turned around to see a triangle-shaped creature with a top hat, skinny black arms an legs, and one eye.

"WHO ARE YOU?!" the traveler screamed.

"I am Bill," the creature said. "the most powerful demon that ever existed! And thank you for summoning me. Now I can take what's mine: THE UNIVERSE! I would thank you, sir. But since I'm evil, it'd be more fun to just KILL YOU OFF!"

If I described what happened next, we'd be bumped up to T rating. Let's just say it wasn't pretty.

"Good," Bill said, pleased. "first, I'll take control of planet Earth. Then I'll go to other planets, and take over THEM! I'LL BE UNSTOPABLE! MWAHAHAHAHA!"

()()()()()()

On another planet somewhere in the universe, the planet if being under attack by Lord Hater. Lots of bird-like creatures are running and screaming in terror. Just like Lord Hater likes to see.

"Soon," Lord Hater announces to the planet. "this planet will be nothing but rock, and I'll be able to use it as my outpost in case my ship gets destroyed! And no one-not even Wander and Sylvia-can stop me!"

Oh, how wrong he was. Hater decided to finish off the planet by launching a missle at it. And firing one was just what he did. But hitting the planet; he wishes! Just as it was about to hit the planet, the missle went flying back at the ship.

"This is the second time one of our missles failed," complained Hater. He looked out the window and saw his missle coming to the ship. He didn't really think about it, but by the time he realized what's gonna happen, it was too late. The missle blew the ship up into a million pieces. Hater, Peepers, the ship pieces, and all the Watchdogs landed on an asteroid orbiting the planet.

How did that missle fly back to Hater's ship? Well, let's head back to the planet, where all the bird-like aliens are cheering for the two space travelers who defeated Lord Hater and saved their planet. Who were these two space travelers?

If you guessed Wander and Sylvia, you are correct. Sylvia had ripped a tree out of the ground, and hit the missle back just before it hit the planet. The king of the planet had went up to the two travlerers and said, "Oh, Wander and Sylvia, we thank you for saving our planet. We will be in your dept forever."

"No need to thank us, sir," Wander said, cheerfully. "It's what we do!"

"That's right," Sylvia added. "Fighting the villians, my thing! Helping others, his thing!"

"Well, still," the king said. "We still thank you for-"

Suddenly, the planet rumbled. Everyone on it felt like they were on a crazy carnival ride. "WHOA," Wander yelled. "I FEEL LIKE I'M GONNA THROW UP!"

"YOU'RE NOT THE ONLY ONE, BUDDY," yelled Sylvia. Suddenly, the planet stopped rumbling, and a bright triangle-shaped creature appeared.

"I AM BILL," it said. "THE MOST POWERFUL DEMON IN THE UNIVERSE! And it will soon be mine! I am going to start with invading planet Earth, then I'll go to other planets and take THEM over! Don't even think of stopping me, or this will happen!" Bill lifted something up. It looked like a traveler, but as a skeleton!

This made everyone scream. "I'll see you when I'm ready to take this planet over!" Bill said as he disappeared. Everyone besides Wander and Sylvia on the planet screamed and panicked.

"Wait," Sylvia said. "don't we know anyone from planet Earth?" Wander thought for a moment, then his eyes lit up in horror.

"DIPPER AND MABEL," he cried. "They don't even know they are under attack!"

"We gotta go warn them," Sylvia said with worry. They formed an orbble around them, and went off to planet Earth.

"WAIT," the king cried. "WHAT ABOUT US?!

()()()()()()

While that was going on, another family in the Tri-State Area, also known as Danville, are going on a vacation to Gravity Falls, Oregon. Two boys named Phineas and Ferb were packing their bags in their room, a teenage girl named Candace was talking on her cell phone, and their mom and dad, Lawrence and Lynda, were getting the car ready.

"Well, I think we're ready to go, Ferb," Phineas said. "Did you pack all the gadgets that could be useful in Gravity Falls?" Ferb gaves a thumbs-up. "That's good." Meanwhile, Candace was talking to her best friend, Stacy, on her cell phone.

"Mom says since Gravity Falls is a forest town," Candace said to Stacy, "it's surrounded by nature. I'm pretty excited."

"That's sounds cool, Candace," Stacy replied. "I wish I could come. I'm gonna miss hanging out with you."

"We're just staying for two weeks," Candace told Stacy. "After that, we'll hang out together for the rest of the summer."

"Do you think your brothers are gonna build some invention while you're there?" Stacy asked.

"Boy, I hope not," Candace answered. "I need a break from busting them."

See, her brothers, Phineas and Ferb, were geniuses. Every day, they build some crazy exciting thing. But right when Candace shows her mom the invention, it disappeared. Like yesterday, Phineas and Ferb built an arcade where you can actually go INSIDE the video games, but right when Lynda was about to see it, the whole thing turned into trash for some reason. Candace had to clean it up, and the boys got pie.

Just then, Lynda walked into the living room.

"Okay, Candace," she told her. "time to get into the car."

"Coming, Mom," Candace replied. "I gotta go, Stace." Then she hung up her cell phone, got her bags, and got into the car along with Phineas and Ferb.

"Okay, kids," Lawrence said. "our vacation starts now."

Phineas looked at his pet platypus, Perry, and said, "Are you excited, Perry?" Perry replied with a platypus noise.

()()()()()()

All the way in the sleepy town of Gravity Falls, two very familiar twins, Dipper and Mabel, have just gotten up and eaten a breakfast of pancakes (to them it was pancake soup, since Grunkle Stan didn't cook it all the way.) After, they got dressed. But Mabel didn't seem like her usual cheery self.

"Mabel, what's wrong?" Dipper asked Mabel with concern.

"I just miss them, Dipper," Mabel replied softly. "I miss Wander and Sylvia."

"It's been three weeks," Dipper said. "You gotta just forget about them."

"But they were NICE ALIENS," Mabel cried. "You can't just forget aliens like that!"

"Well, you're gonna have to," Dipper told her. Mabel then sighed and said yes. Just then, Soos, the Mystery Shack's man-child, came in.

"S'up, dudes?" he greeted.

"Hey, Soos," Dipper replied. "I'm gonna try to find zombies today. Lots of people have came out of the woods and claimed to see lots of zombies walking around, and I wanna see if it's true. Wanna help?"

"Sure, dude," Soos agreed. "Seeing a zombie is a once in a lifetime experience."

"Yeah right," Grunkle Stan said. "Those 'zombies' were just people with the stomach flu. They just showed it on the news."

"Aww, man," Dipper, Mabel, and Soos all said sadly.

**2 hours later:**

Wander and Sylvia were coming up fast to Earth. The only thing stopping them was time. "Okay, buddy," Sylvia told Wander. "We go to Gravity Falls, warn Dipper and Mabel, and then we try and stop that demon."

"I just hope we aren't too late," Wander said. "Dipper and Mabel are nice folks. They don't deserve to die." They got into Earth's orbit, but just then, their orbble bursted, and they ended up falling. Fast.

Wander and Sylvia screamed as they fell. They only had a little bit of orbble juice left, and they needed it to leave Earth. They fell and fell, but luckily, they landed right in the town of Gravity Falls.

While they were falling, Dipper and Mabel were walking to the Gravity Falls Arcade, they saw some sort of meteor fall from the sky. "Dipper?" Mabel ased, pulling her brother's sleeve. "What is that?" The flame ball seemed to be coming for them. "GET DOWN," Dipper cried. The twins ducked, and the flaming ball missed them and landed in the grass right next to them.

"What was that?" Dipper asked. They turned around and saw two figures stand up. The smoke went away, do you know who the two figures were? Wander and Sylvia.

"We're back," Sylvia told the twins.

**How did you guys like the chapter? It's hard to make a good sequel to such a successful story. I hope you give me LOTS of support on this story, and I also hope this story turns out to be bigger than the first. Anyways, see you in the next chapter! This is CrossoverGuy21 signing out.**


	2. 2: Meeting P&F

**Hey guys! Sorry for the long hiatus, but I had other stuff in my life to do, plus I need to work on my Dead over Dawn story. But, here it is: Phineas and Ferb Wandering over Gravity Falls: Chapter 2!**

The Flynn-Fletcher family were only ten minutes away from their hotel in Gravity Falls. But on the way there, Phineas heard Perry's stomach rumbling.

"You must be hungry, Perry," Phineas said. He looked in his bag and found Perry's favorite treats. But the canister was empty. "Sorry, Perry, we got to wait until we get there so I can buy some more." Then Perry's stomach growled even louder.

_I can't believe I have to basically starve here, _Perry thought as his stomach continued to rumble and gurgle. Perry could've swarn that his stomach actually moved with the rumbling. Finally, they got to their hotel, and checked in.

"This hotel is pretty nice," Lynda said as they entered their room. Lawrence put all the bags on the table. Perry's stomach growled again.

"Oh, that reminds me, Ferb and I are going to buy some food for Perry, Mom," Phineas said. "We'll be back in a little bit."

"Don't forget to bring a map," Lynda told the boys. "I don't want you two to get lost." Phineas picked up a map and key card, and the boys ran to the store.

"Hey, Candace," Lynda said. "there is a lot of wildlife and scenery in this town. Why don't you go and explore?"

"Good idea, Mom," Candace replied. She got a key card and left the hotel.

()()()()()()

B**ack to Dipper, Mabel, Wander, and Sylvia:**

"YAY!" Mabel cheered. "YOU CAME BACK!"

"But only for a little while," Sylvia replied. Mabel had a look of confusion mixed with sadness.

"We have to warn you about something," she continued.

"Yeah," Wander added. "A demon named Bill plans to destroy the universe, starting with this planet."

"BILL?!" Dipper and Mabel yelled in unison.

"Wait, you've HEARD of this guy?!" Sylvia asked.

"HE ALMOST DESTROYED US," Dipper said. "He went into my grunkle's mind and-"

"Grunkle?" Wander interupted. "What's a Grunkle?"

"Great Uncle," Dipper said, annoyed. "As I was saying, he went into his mind and almost stole the code for the safe that holds our house's deed!"

"He's powerful, dangerous, and evil," Mabel added. "If he gets into your mind, it's game over for you."

"Man," Sylvia said. "this is more serious than we thought."

"Um, ya THINK?!" Dipper yelled. "We need to find a way to defeat Bill before the universe is destroyed."

"How will we do that?" Wander asked. "The way you described him, he sounds like he can't be defeated." Suddenly, two kids ran into Dipper and Mabel.

"Oh, sorry about that," the red haired kid said. "we just needed to get home to our starving pet." He then picked up the canister of pet food. "Name's Phineas, by the way." Then he pointed to the green haired kid. "And this is my brother, Ferb."

"I'm Dipper," Dipper said. "And this is my sister, Mabel." Then Phineas and Ferb turned around to see Wander and Sylvia.

"Is that Wander and Sylvia?" Phineas asked.

"How did you know?!" Dipper asked, surprisingly.

"Our family saw the news report on TV," Ferb said. "We thought it was pretty amazing."

"Well, we need to go now," Sylvia told the boys. Then Dipper, Mabel, and Wander got on Sylvia's back.

"Okay, then," Phineas said. "We were going to explore the forest later, so-"

"WHAT?! NO!" Dipper yelled. Phineas and Ferb looked confused. _Great, _Dipper thought. _Now I gotta tell them about the dangers of this town. And when I do, they'll think I have a screw loose or something._

"Well?" Phineas asked. "Why can't we go into the forest?"

"Because you'll DIE," Dipper told them. Mabel looked at Dipper and did the hand signal for "no." But Dipper ignored it and took out his journal.

"Gravity Falls," Dipper explained, "is not a normal town..."

()()()()()()

**Meanwhile, in the town...**

Candace had been walking around for ten minutes. During her walk, she saw two cops arresting someone, but then they saw an ad for free donuts, and they ran to the store, letting the criminal go. She had a feeling everyone was like that in this town. Suddenly, someone bumped into her.

"Ouch," Candace moaned. "what was that for?"

"Oh, I'm very sorry," the person said. She appeared to be a teenage girl. She had reddish brown hair, a raccoon skin hat, a green flannel shirt, and freckles. Then she helped Candace up. "My name's Wendy," she said. "Sorry 'bout running into ya."

"It's okay," Candace told her. "My name's Candace."

"You aren't from around here, are you?" Wendy asked.

"Nope," Candace said. "My family is only staying here for two weeks."

"And you don't have any friends from here?"

"No, but my best friend Stacy is all the way back home." Suddenly, a guy with black hair, a hoodie, and skinny jeans came up to Wendy on a bike.

"Come on, Wendy," he said. "Can't you forgive me?"

"I will NEVER forgive you, Robbie" Wendy told him. "You hurt me too much. I don't even wanna see you again."

"Fine," the guy said, and he biked away.

"Who was that?" Candace asked.

"My ex-boyfriend, Robbie," Wendy told Candace. "He stood me up multiple times, and right when I was about to forgive him, he tries to hypnotize me into staying with him. He's a complete jerk."

"He looks like the complete opposite of my boyfriend, Jeremy," Candace said.

"Well, do you wanna hang out or something?" Wendy asked.

"Sure," Candace agreed. Then the two walked together and explored Gravity Falls.

()()()()()()

**Back to Phineas, Ferb, Wander, Sylvia, Dipper, and Mabel:**

"Gravity Falls," explained Dipper. "is not an adverage town. In fact, nothing about it is adverage. It's full of weird stuff, like ghosts, zombies, anything paranormal, abnormal, or supernatural, you can find in Gravity Falls."

"And," said Phineas. "how do you know all this?"

"This," Dipper said as he held the journal up. "This journal records the strange events and secrets of this town. And me and my sister have actually seen this stuff."

"Yeah," Mabel added. "We've seen gnomes, merpeople, wax figures coming to life, monsters, lots of things."

"Ferb and I have done amazing things too," said Phineas. "We have seen the legendary Chubacabra."

"And," Ferb added. "built amazing things."

"YOU?" Sylvia asked. "Im guessing you built a small fort."

"We have built a fort," Phineas told her. "but it wasn't small."

"Prove that you've built amazing things," Sylvia said. Phineas and Ferb got the materials they needed, and half an hour later, they have built some kind of vehicle.

"This is a hover craft," said Phineas.

Dipper, Mabel, Wander, and Sylvia were stunned. They just stood there, their jaws hanging down.

"That's..." said Dipper.

"Incredible..." Sylvia said as well.

"And you do this kind of stuff every day?" Mabel asked.

"Yes, we do," Phineas told her. "We have built a roller coaster, a rocket, an improved tire swing..."

Dipper than got an idea. "Have you guys ever saved the WORLD?" he asked.

"Many times," Phineas told Dipper. "Why?"

"We need your help," Dipper continued. "A demon named Bill is going to destroy Earth. We need to find a way to defeat him, but we need help."

"Wait, did you say DEMON?" Phineas asked, startled. "That is SUPER serious!"

"I know," said Dipper. "Will you help us?"

Phineas looked at Ferb. "What do you say, Ferb?" he asked. Ferb gave a thumbs up, and Phineas looked back at Dipper. "Okay, we'll help."

"Thank you," Dipper happily said. "Let's go to our Grunkle's house. We'll come up with a plan there."

"Hold on," Phineas said. "We need to feed Perry. Can you give us your address?"

"Sure," Mabel said. "Just look for the building with the sign that says 'Mystery Hack.'" Phineas and Ferb just looked at her, confused. "The 'S' fell off of the sign."

"Oh," Phineas said. "We'll meet you guys later." Then the guys ran off.

**FINALLY this chapter is done! I don't want to make the same mistake I do with all my stories; progressing it so soon. I only have seven actual chapters on the prequel to this story, so I wanna make more. Give me ideas on what the next chapter should be about! Don't forget to favorite, follow, and review. This is CrossoverGuy21 signing out.**


	3. Writer's Block

**Guys, I am so sorry for not updating for so long, but...**

**I HAVE A HUGE CASE OF WRITER'S BLOCK!**

**I want to think of inspiration for the next chapter (or any story,) but I just can't due to other stuff in my life.**

**I want to finish Phineas and Ferb Wandering over Gravity Falls, but I got no inspiration or time to work on it.**

**So, do you have any inspiration for future chapters, can you tell me them please?**

**I'll try to work on other stories and future chapters of Phineas and Ferb Wandering over Gravity Falls, but for now, I got no inspiration.**

**This is CrossoverGuy21 signing out.**


End file.
